jestjs - 手动模拟未被拾取

Question

Jest 不提供我的手动模拟。一切似乎都在正确的目录中。我错过了什么？

src/adapters/__mocks__/Foo.js

const spy = jest.genMockFromModule('../Foo')

function doStuff() {
  return { source: 'mock' }
}

spy.doStuff = doStuff
module.exports = spy

src/adapters/Foo.js

class Foo {
  doStuff() {
    return { source: 'real' }
  }
}

module.exports = Foo

src/adapters/__tests__/Foo.js

const Foo = require('../Foo')

test('Foo', () => {
  const foo = new Foo()
  expect(foo.doStuff()).toEqual({ source: 'mock' })
})

测试输出:

expect(received).toEqual(expected)

    Expected value to equal:
      {"source": "mock"}
    Received:
      {"source": "real"}

    Difference:

    - Expected
    + Received

      Object {
    -   "source": "mock",
    +   "source": "real",
      }

      3 | test('Foo', () => {
      4 |   const foo = new Foo()
    > 5 |   expect(foo.doStuff()).toEqual({ source: 'mock' })
      6 | })
      7 |

      at Object.<anonymous>.test (adapters/__tests__/Foo.js:5:25)

Jest 版本:“jest-cli”:“^23.0.0-alpha.0”

从长远来看，尝试了这个，但没有奏效。没有找到模拟，只是给了我 undefined 正如我在调用 doStuff() 时所期望的那样

src/adapters/__tests__/Foo.js

//TREID this but didn't work
jest.mock('../Foo')

const Foo = require('../Foo')

test('Foo', () => {
  const foo = new Foo()
  expect(foo.doStuff()).toEqual({ source: 'mock' })
})

Answer 1

试试下面的代码，这里的问题是我们模拟 ES6 类的方式，基本上，有 4 种方法可以模拟 class，如文档中所述

https://facebook.github.io/jest/docs/en/es6-class-mocks.html

src/adapters/__mocks__/Foo.js

const mock = jest.fn().mockImplementation(()=>{
   return {
       doStuff: jest.fn(()=>({source: 'mock'}))
   } 
});

module.exports = mock;

src/adapters/__tests__/Foo.js

jest.mock('../Foo');

const Foo = require('../Foo');

test('Foo', () => {
    const foo = new Foo();
    expect(foo.doStuff()).toEqual({ source: 'mock' })
});

(或)

内联模拟也可以工作

src/adapters/__tests__/Foo.js

jest.mock('../Foo', () => {
    return jest.fn().mockImplementation(() => {
        return {
            doStuff: jest.fn(() => ({ source: 'mock' }))
        }
    });
});


const Foo = require('../Foo');

test('Foo', () => {
    const foo = new Foo();
    expect(foo.doStuff()).toEqual({ source: 'mock' })
});